In advanced NSCLC, a specific subgroup of patients exhibits synchronous oligometastatic disease (sOMD), characterized by a low metastatic burden identified at initial diagnosis. Given the established association of cachexia and sarcopenia with reduced survival, these features could help guide decisions on the appropriateness of radical intervention. This retrospective multicenter investigation included all patients with thoroughly staged (via FDG-PET and brain imaging) sOMD fulfilling the EORTC criteria. The study evaluated associations between cachexia and/or sarcopenia and clinical outcomes. Among 439 patients identified from 2015 to 2021, 234 were eligible and formed the study population. Median age was 67 years, 52.6% were male, and the median number of metastases was 1. Cachexia was present in 46 (19.7%) patients, sarcopenia in 34 (14.5%), and both conditions co-occurred in 21 (9.0%). With a median follow-up of 49.7 months, median progression-free survival (PFS) and overall survival (OS) reached 8.6 and 17.3 months, respectively. Patients without cachexia or sarcopenia exhibited a trend toward improved PFS compared with those affected by either or both. Multivariate analysis revealed no independent association between cachexia or sarcopenia and inferior survival, irrespective of radical treatment delivery. Elevated CRP levels correlated with poorer survival and may represent a useful prognostic marker to support selection of patients likely to benefit from LRT. Despite standardized oligometastatic classification and comprehensive staging, the analyzed subgroups were small. Consequently, larger prospective studies are warranted to confirm these observations and further elucidate the underlying hypothesis.
